Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session T04: Surfaces, Interfaces & Materials |
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Sponsoring Units: DCP Chair: Jingshan Du, Pacific Northwest National Laboratory Room: Room 127 |
Thursday, March 9, 2023 11:30AM - 11:42AM |
T04.00001: On Chip Sensing of Biochemical Molecules with GaAs PIN Diodes Jonathon M. Cain, Abdel F. Isakovic, Christopher Alpha, Tamador Alkhidir, Deborah L Gater We demonstrate that Schottky contacted GaAs PIN conducting diode can be used as a viable sensor for detecting biochemically relevant molecules. The microfluidic chip contains an array of cylindrically shaped diodes, oriented so the liquid solution can be placed in a trough of the chip with the liquid surrounding the diodes. For the test of the functionality of the sensor, we use DI water, deuterated water, PBS solution, and a series of amino acid solutions with controlled pH levels. We focus our studies on the transport properties, including differential conductance and impedance spectroscopy. Also, we examine the C-V measurements as the various electrolytes and diode biasing conditions have different effects on the Debye length. Next, we address the issue of noise in such (bio)chemical sensors in relation to variations in the molecular structure of solid-liquid interface. Wealth of data coming from this sensor calls for the use of advanced data analysis techniques, so we demonstrate how one can use machine learning to optimize such sensor. |
Thursday, March 9, 2023 11:42AM - 11:54AM |
T04.00002: First-principles study of second-order nonlinear susceptibility of water adsorption layer on Pt(111) surface Jun Haruyama, Toshiki Sugimoto, Osamu Sugino Basic understanding of metal/water interface is essential for electrochemical devices, and water adsorptions on metal surface are one of the simplified systems for investigating the interface property. Recently, second-order nonlinear susceptibilities χ(2) of H2O layers on Pt(111) (ωIR ∼ 3000 cm-1) was obtained by sum-frequency generation spectroscopy, and the observed spectra revealed the structure of hydrogen-bond network of water layers. [1] The aim of this study is to establish calculation of χ(2) by first-principles method and to obtain χ(2) spectra of Pt(111)/H2O layers. By applying the density functional perturbation theory (DFPT) [2] and effective screening medium (ESM) method [3], we have succeeded in obtaining the χ(2) spectra of Pt(111)/H2O layers. In the presentation, we will explain the detailed calculations, and discuss the comparison between theoretical calculations and the experiment. |
Thursday, March 9, 2023 11:54AM - 12:06PM |
T04.00003: First-principles investigations of interfacial effect induced by spontaneous polarization of ABO3 on magnetic anisotropy energy of Fe layer Dameul Jeong, SEOUNGHUN KANG, Young-Kyun Kwon Lowering the spin-switching energy in spin-based devices is indispensable for their performance enhancement. As a potential way of reducing the spin-switching energy, we explored the effects of ferroelectric (FE) materials on the magnetic properties of ferromagnetic (FM) materials using first-principles density functional theory. We select an iron monolayer as a typical FM material, which is placed on one of various ABO3 perovskites chosen as prototypical FE materials, where A and B are the alkaline earth (A=Ca, Sr, or Ba) and group 4 transition metal (B=Ti, Zr, or Hf) elements, respectively, and O is oxygen. Then we investigate the correlation between the spontaneous polarization of an ABO3 perovskite and the magnetic anisotropy energy (MAE) of the Fe monolayer. It is found that the MAE of the iron monolayer is influenced not only by the field effect of FE polarization but also by the structural modification at the interface between FE and FM. Surprisingly, the electric field effect due to polarization is rather insignificant on the MAE causing a small change of up to only a few μ eV. The change in the magnetic moment due to the atomic displacement at the interface has a more correlation with MAE. We also performed machine learning (ML) to describe the universal behavior of FM MAE in the presence of FE. The optimized descriptor obtained by ML indicates that the most relevant features are the magnetic moments of certain atoms at the interface rather than the spontaneous polarization of FE materials as found in our DFT study. |
Thursday, March 9, 2023 12:06PM - 12:18PM |
T04.00004: Synthesis and Exploration of Heusler Intermetallics as Potential Catalysts Md. Fahel Bin Noor, Nusrat Yasmin, Tiglet Besara The ternary intermetallic Heusler alloys, comprising the formula X2YZ (X and Y are transition metals, while Z is a p-block element), can be found in a wide range of elemental combinations. They make excellent candidates for the quest for efficient catalysts due to their electrical tunability, which may be achieved by altering the composition or substituting components. Heusler alloy samples have been synthesized using mechanical alloying. This traditional method for making coarse-grain Heusler compounds involves mechanical grinding and post-annealing. X-ray diffraction was used to confirm the structures and to determine the grain size of the ball-milled compounds. Raman spectroscopy was used to investigate the catalytic activity of the alloys for the hydrogenation of unsaturated hydrocarbons, and its dependency on time and temperature. |
Thursday, March 9, 2023 12:18PM - 12:30PM |
T04.00005: Temperature dependence of nuclear quadrupole resonances in 235U-depleted Cs2UO2Cl4 Sejun Park, Eric D Walter, Robert G Surbella, Chuck Z Soderquist, Gabriel B Hall, Sergey I Sinkov, Herman Cho In this work, we report zero field 35Cl nuclear quadrupole resonance (NQR) for 235U-depleted Cs2UO2Cl4. A single peak indicates that all Cl ions are at an equivalent site. A good agreement between electric field gradients obtained from the spectrum and a DFT calculation confirms partial charge transfer between Cl and U. The resonance frequency decreases linearly with temperature at high temperatures and with decreased slope at lower temperatures. The temperature dependence of the spin-lattice relaxation time shows a quadratic decrease at high temperature and accelerated change at low temperature. Calculations using phonon induced charge fluctuation in covalent hybridization show good agreement with experimental observations. By comparing experimental data and theory, we obtained a Debye’s temperature, TD=100 K. An estimate of the contribution of Cl ions to the U NQR frequency shifts and spin-lattice relaxation can be obtained from this analysis. |
Thursday, March 9, 2023 12:30PM - 12:42PM |
T04.00006: Pd6, Ag8, and Pd6/Ag8 particles supported on pristine graphene-like cluster: A DFT cluster approach Carlos Quintanar Graphene is an only one-atom-thick bi-dimensional sheet with a unique electronic structure. It is a zero-gap semiconductor, where the electrons mimic massless relativistic particles. Because of its interesting electron properties, graphene is a promising material for supporting catalysts like palladium, silver, and Pd-Ag. The pristine graphene was modelled by using a 306 planar cluster, where Pd6, Ag8, and Pd6/Ag8 particles were adsorbed. |
Thursday, March 9, 2023 12:42PM - 12:54PM |
T04.00007: Ab Initio Calculation of Surface-Controlled Photocatalysis in Multiple-Phase BiVO4 Wenyu Zhang, Qiang Gu, Jia Shi Bismuth vanadate (BiVO4) is one of the semiconductors that are often used for photoelectrochemical water splitting, because of its low band gap and various crystalline phases. Using density functional theory (DFT) based calculations, the surface properties, electronic structures, and photocatalytic properties of different facets are obtained. These include the (001), (011), and (101) facets that are truncated from ms-BiVO4 and the comparable {001}, {011}, and {101} facets that are produced by means of cleavage from ts-BiVO4. Our findings show a surface stability order of (001)/{001} > (101)/{101} > (011)/{011}. The (011) and {011} facets present distinct surface properties owing to the asymmetric a-–b plane of ms- BiVO4, in contrast to ts-BiVO4. The work function of the {011} facet is dramatically decreased by 1 eV in comparison to the other facets, resulting from a positive surface dipole with an open lattice. Surface (001) shares geometric and electronic structures characteristics with {001}, and surface (101) possesses identical features with {101}. Furthermore, we confirm that the discrepancies between the (011) and {011} surfaces in facet morphologies and electronic structures are one of the reasons accounting for the distinct photoelectrochemical activities of ms- and ts-BiVO4 from experiments. |
Thursday, March 9, 2023 12:54PM - 1:06PM |
T04.00008: Isosteric heat of adsorption for carbon dioxide on Biochar Saikat Talapatra, Brice Russell, Nathanial Smith, Xingmao Ma, Aldo Migone Results of adsorption isotherm measurements for carbon dioxide on commercially available Biochar will be presented. Volumetric adsorption isotherms were measured at various temperatures between 273 and 315 K. The isosteric heat of adsorption for carbon dioxide on the Biochar has been obtained from these isotherms. We found that the isosteric heat of adsorption for carbon dioxide on the Biochar is of the order of 300 meV. These results will be discussed and compared with adsorption carbon dioxide on other carbon based porous materials. |
Thursday, March 9, 2023 1:06PM - 1:18PM |
T04.00009: Elucidating Trivalent Ion Adsorption at Floating Carboxylic Acid Monolayers Ahmet Uysal, Srikanth Nayak, Raju R Kumal We study trivalent neodymium adsorption on floating arachidic acid films at the air-water interface by two complementary surface specific probes, sum frequency generation (SFG) spectroscopy and X-ray fluorescence near total reflection (XFNTR). Neodymium ions compensate the surface charge of the arachidic acid without any charge reversal. However, the interfacial water goes under significant reorganization, even after the charge compensation. Controlling the Debye length with excess background salt, we reconcile the apparent contradictions between X-ray and surface spectroscopy experiments. These results show that the total coverage of neodymium ions is not enough to describe the complete picture at the interface and interfacial water and ion coverage needs to be considered together to understand more complex ion adsorption and transport processes. |
Thursday, March 9, 2023 1:18PM - 1:30PM |
T04.00010: First-principles simulations of vibrational spectra of electrified Si/water interfaces Zifan Ye, Giulia Galli Probing electrified interfaces is critical to understanding many phenomena relevant to transient electronics, photoelectrochemical modulation of biological cells and tissues, and photoelectrocatalysis. However, it remains challenging to devise atomistic models of electrified interfaces that can be used to predict electrochemical processes at the microscopic scale. We investigated an electrified hydrogenated silicon/water interface using first-principles molecular dynamics simulations (FPMD) and the Qbox code (http://qboxcode.org/), and we predicted capacitive and Faradaic currents, consistent with experimental results [1]. We then used FPMD to study the vibrational properties of the interface, including Raman spectra. Our analysis in terms of effective polarizabilities reveals differences in hydrogen bonding between the pristine and electrified interface, as well as differences in molecular orientation. Work is in progress to compare simulation results with experiments. |
Thursday, March 9, 2023 1:30PM - 1:42PM |
T04.00011: Realizing High Thermoelectric Conversion Efficiency in p-type AgSbTe2 Alloys YU ZHANG, Bed Poudel, Amin Nozariasbmarz, WENJIE LI, Andreu Cabot, Shashank Priya Thermoelectric generators enable the direct conversion between heat and electricity, having applications both for refrigeration and power generation. The flourishing growth of thermoelectric materials with high figures of merit zT in the last decade certainly requires parallel enhancement on conversion efficiency of thermoelectric devices. Herein, the thermoelectric performance of p-type AgSbTe2-based materials is optimized though doping with S, to reach an outstanding maximum figure of merit zTmax of 2.0 and an average ZTave of 1.3 over the temperature range 300 - 670 K. The exceptional performance arises from the highly improved power factor, which comes from optimized carrier density and vastly improved Seebeck coefficient enabled by the contribution of band flattening near the top of valence band. This material is used to fabricate single-leg thermoelectric modules reaching record energy conversion efficiencies up to 10%. These results highlight an effective strategy to engineer high-performance thermoelectric material for efficient waste heat recovery in medium temperature range. |
Thursday, March 9, 2023 1:42PM - 1:54PM |
T04.00012: Dispersion-induced non-Markovian effects for emission spectra of exciton-plasmon systems Tigran V Shahbazyan We study the role of non-Markovian effects, originating from optical dispersion of metal dielectric function, in the emission spectrum of a quantum emitter resonantly coupled to a surface plasmon in a metal-dielectric structure as the system transitions to strong coupling regime. By using a quantum approach to interacting plasmons that incorporates the effects of dispersion and losses in the coupling parameters, we obtain analytically the emission spectrum for an exciton-plasmon system with characteristic size below the diffraction limit. In the strong coupling regime, the dispersion-induced non-Markovian effects lead to pronounced changes in the emission spectra by causing inversion of spectral asymmetry, as compared with classical and quantum models based on the Markov approximation, which results in a strong enhancement of the lower frequency polaritonic band. |
Thursday, March 9, 2023 1:54PM - 2:06PM |
T04.00013: Impact Synthesis of Prebiotic Organophosphoric Compounds in Schreibersite Materials RICCARDO DETTORI The meteoritic mineral schreibersite is a proposed abiotic source of phosphorus for phosphate ion (PO4–) production, needed for nucleobases, phospholipids, and other life building materials. Schreibersite could have acted as both a source of elemental phosphorus and as a catalyst, and the hostile conditions on early Earth could have accelerated its degradation in different environments. By means of ab initio molecular dynamics calculations, we characterize Fe3P schreibersite in its bulk phase and we investigate the stability of its low Miller index surfaces. Furthermore, we study water absorption on its most stable facet providing an important first set of bounding calculations in elucidating possible scheibersite corrosion and phosphate ion production. Finally, an approximate quantum simulation model in the framework of Density Functional Tight-Binding (DFTB) is derived, in order to carry shock-compression calculations and characterize schreibersite reactivity in acqueous environments under extreme thermodynamics conditions. |
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